Compressed-air engine



Aug.27, 1929. K' WITT|G" 1,726,462

COMPRESSED AIR ENGINE Filed Oct.- 9, 1925 -withm the en Patented Aug.27,1929.

UNITED sm'rss PATENT osrlcs.

KARL WITTIG, OF Gm.

eonaiissEn-m Imam Application fled october 9, 1825, serial Io. 61,529,and in Germany October 22,

is usual to employ compressed and therefor 5 heated air furnished by acompressor to drive the subterraneous apparatus. It is more particularlyapplicable to air motors of the type comprising radial blades or vanesadapted to rotate within a substan-- tially crescent shaped workingchamber.

In connection with compressed air engines of such kind which are used inmining operations, it is necessary to prevent the extensive coolingeffect of the compressed air upon expandin on the exhaust side of theengine from reezing water vapour contained in the exhaust air and thusrestrictin or choking up the exhaust passage, ..as this disadvantageprevents the complete consumption of the compressedair by expansion. Theprovision of water separators for previously withdrawin from the air thewater vapour container? therein has proved to be uneconomical anduncertain, while other suggestions such, for instance, as the provisionby means of special separate auxiliary compressors forsupplying heat, apar to be unpracticable and intricate.

he object of the present invention is to prevent, without providing anyseparate map chines or devices, the formation of ice in the exhaustpassages while at the same time, obtaining a much greater expansion inthe engine than was previously possible. By the employment of a device,which in no way necessitates any. great alteration .in the constructionof the usual of compresse air engine, no considera 1e expenditure isincurred.

According to the invention, this object is att -'ned by causing the warmworking compressed air of admission such as it is furnished by acompressor, or a portion .thereof, to flow round the exhaust side of theengine casing before reaching the actual worln'ng portion of. theengine, so as to heat in some respect the exhaust rt of the enginecasing and to prevent f eezing of water vapour within the exhaustopening, 5 which otherwise would take place on account of the extensiveexpansion of the air on the. exhaust side, a portion of the exhaust airbeing also arranged to be again compresse e and reintroduced into the.let chamber is indicated at a.

. part use compressed air admitted working portion thereof afterpreviously dellvermg its' heat of compression to the casing and rotor.

The invention will now 'be described by way of example with referenceto'the accompanying drawing illustrating a compressed air engine havingrotating vanes and a working space of substantially crescent shapedcross section;'

Figure 1 being a vertical. sectional view, and Figure 2 a horizontalsectional view thereof, illustrating the arrangement of-the heatingsleeve or jacket aroundthe motor casing.

Referring now to the drawing it will be seen that a rotor r'havingradially movable vanes s is arranged eccentrically to the casing A, thusforming a working space of substantially crescent. shaped cross sectionbetween theperiphery of the rotor and the casing. The inlet chamber ofthe engine is indicated at b, the inlet port below the rotor at f andthe exhaust chamber'situated onthe side of the rotor opposite to the in-The casing A is provided with a hollow sleeve or jacket a extending for'the most around the exhaust side of the casing, a conduit d forsupplying the working com ressed air to the engine being connected tothis sleeve or jacket the outlet of which on the other hand is connectedby means of a pipe e or directly to the inlet chamber b of the engine.The hot or heated air, after it has given ofi-a part of its heat in thejacket a to the walls of the casing A, flows through d the port f intothe compartments formed between the vanes s of the rotor 1-, which isthereby rotated in the direction of the arrow (Figure 1) and du 'n the.recess of expansion flows into the e' aust c amber ,0. I The object ofthese arrangements is to nerally at a temperature of 20 to 50 to thuskee same at a temperature which does not w ow of water vapour containedin the air, t e heat thus trans- .to firstflow around the exhaust sideof the'engine and ferred :to the exhaust part of the engine casing thuscompensating to a great extent the cooling effect which is due to theextensive expansion of the workingair at its exd beast and otherwisewould cause freezing of the water vapour. This prevents to a greatextent the danger of ice forming and adhering in the exhaust passage ofthe engine, thus avoiding restricting or choking up of this passage, aswould be the case in mine compressed air motors that have no protectivearrangementsof such kind.

In order to ensure that the heating action near to the exhaust chamber 0adjacent the sleeve or jacket a, and constitutes as does '0 a part ofthe body of the casing.

Inasmuch as the rotor compartments as they pass the wall u are cut offfrom the exhaust chamber 0 a remaining portion of the cold expandedexhaust air is here compressed again. This spontaneously heatedcompressed air is continuously supplied to the'inlet ort .but gives offa considerable portion 0? its eat previously to the casing, the rotorand particularly to the Wall 10. In this manner byvreason of the supplyof hot air to the engine through'the jacket a and of the heat producedby the auxiliary compression, the casing and particularly the partsurrounding the exhaust, is kept warm in all circumstances, thuspreventing the freezing of the water vapour at the exhaust side of theengine.

The invention thus consists in utilizing the hot or'previously heatedworking compressed air to heat the casing on the one hand, and on theother hand causing the engine itself to act as a compressor so that bycompressing a portion of the expanded air additional heat is generatedwhich is conducted to the casing of the engine.

The invention is evidently not limited to the particular constructionand arrangement of parts herein described but various modifications maybe made therein without exceeding the scope of the invention. Forinstance, instead of causing the whole of the working compressed air toflow through the jacket a a portion of this air may be diverted andconveyed to the neighbourhood of the exhaust for heating purposes.

\Vhat I claim is: A compressed air motor of the kind described,comprising a casing, an admission and an exhaust port thereon, acompressed air jacket on said casing extending up to said exhaust port,means to supply said jacket with compressed air preliminarily to the usethereof for working, a rotor eccentrically mounted in said casing,radially movable vanes on said rotor, said casing having two wall partsbetween said ports to form with the rotor, the one, a crescent shapedcompressed air expansion chamber for the operation of compressed airupon the rotor vanes,the other, a crescent shaped exhaust aircompressing chamber between the exhaust and the admission ports ofthecasing for taking in and compressing a portion of the exhaust air, andconnecting means between said jacket and the admission port foradmitting the compressedair for working, substantially as and for thepurpose described.

In witness whereof I have hereunto signed my name this 28th day ofSeptember, 1925.

KARL WITTIG.

